Mechanism of the sperm acrosome reaction

描述（由申请方提供）：受精发生在精子顶体反应完成后，这是一种在配子粘附期间触发的分泌事件。 在哺乳动物中，分泌是由ZP 3触发的，ZP 3是卵细胞外基质的糖蛋白成分，或透明质酸（ZP）。本项目的长期目标是了解ZP 3在顶体反应中的信号转导机制。我们以前已经表明，瞬时受体电位典型（TRPC）通道在ZP 3诱导的小鼠精子顶体反应中起着至关重要的作用。这项研究计划的重点是TRPC效应蛋白，参与ZP 3信号启动下游的事件。使用酵母双杂交，我们已经确定了一种新的精子蛋白，enkurin，它结合TRPC通道和磷脂酰肌醇-3-磷酸（PI 3 K）。恩库蛋白-PI 3 K相互作用的证明促使我们研究PI 3 K在顶体反应中的作用。我们目前的初步数据表明，ZP 3刺激生产的PI 3 K产品磷脂酰肌醇-3，4，5-三磷酸（PIP 3）。需要PIP 3来驱动顶体反应。有两个具体目标：1）将产生雄性生殖系enkurin无效小鼠以确定enkurin功能在精子中的功能;和2）鉴定小鼠精子中ZP诱导的AR期间PI 3 K的下游效应物;初步数据表明AKT参与小鼠精子中的ZP-顶体反应信号传导途径。下一步是确定顶体胞吐过程中这种激酶的底物。 项目简介：当施肥不受限制或受到阻碍时，就会产生健康问题。在这方面，顶体反应是哺乳动物配子相互作用过程中的一个重要调控事件，不受调控的胞吐作用与受精失败有关。这些研究定义了下游效应蛋白，它们是ZP 3信号通路的重要组成部分，并可能为控制受精提供新的靶点。

DESCRIPTION (provided by applicant): Fertilization occurs after completion of the sperm acrosome reaction, a secretory event that is triggered during gamete adhesion. In mammals, secretion is triggered by ZP3, a glycoprotein component of the egg's extracellular matrix, or zona pellucida (ZP). The long range goal of this project is to understand the mechanism of ZP3 signal transduction during the acrosome reaction. We have previously shown that transient receptor potential canonical (TRPC) channels play an essential role in ZP3-induced acrosome reaction in mouse sperm. This research proposal focuses on TRPC-effector proteins that participate in events downstream of ZP3 signal initiation. Using a yeast-two hybrid we have identified a novel sperm protein, enkurin, which binds to both TRPC channels and phosphatidylinositol-3-phosphate (PI3K). The demonstration of an enkurin- PI3K interaction prompted us to investigate a role for PI3K in the acrosome reaction. We present preliminary data showing that ZP3 stimulates the production of the PI3K product phosphatidylinositol-3,4,5-triphosphate (PIP3). PIP3 is required to drive the acrosome reaction. There are two specific aims: 1) A male germline enkurin null mouse will be generated to determine the function of enkurin function in sperm; and 2) Identify downstream effectors of PI3K during the ZP-induced AR in mouse sperm; preliminary data suggests that AKT is involved in the ZP-acrosome reaction signaling pathway in mouse sperm. The next step is to identify the substrates of this kinase during acrosomal exocytosis. PROJECT NARRATIVE: Health problems are posed when fertilization is either unbounded or impeded. In this regard, the acrosome reaction is an important regulatory event during mammalian gamete interaction, with unregulated exocytosis associated with failure of fertilization. These studies define downstream effector proteins that are essential components of the ZP3 signaling pathway and may provide new targets for the control of fertilization.